High average power lasers in the kilowatt range requires proper beam distribution to avoid thermal damages and increase the throughput of processes. For megahertz pulse repetition rate lasers or continues wave lasers, ultra-fast beam deflection provided by polygon mirror scanners has been demonstrated as appropriate solution. The utilization of a polygon mirror together with a single axis galvo scanner for a second distribution direction is suitable for two-dimensional scan field processing and position true treatments of moving substrates. Using a double reflecting polygon mirror has advantages regarding low optical distortions and pivot point migration. Furthermore, a polygon mirror with a free aperture of 30 mm allowing high power laser handling without negative effects on the optics. Nevertheless, a coating for wavelength other than infrared was not able, yet. A new mirror design has been investigated to allow high reflective coatings in the ultraviolet wavelength range of 343-355 nm. Laser drilling of silicon wafers has been performed to demonstrate an application with a high demand of precision. The UV-coated double-pyramidal polygon mirror has been integrated in a two-dimensional scanner and was utilized together with a 10 ps pulsed 355 nm laser. Holes with an exit diameter below 10 µm were achieved.